A study of cell-wall site interaction of uranyl ion adsorbed by non-proliferative suspensions of Mycobacterium smegmatis at pH 1 has been carried out using extracts of arabinogalactan-peptidoglycan and phospholipids obtained from whole cells treated under sorption conditions. Evidence for binding of UO22+ by constituent P-lipids was provided by comparative 31P-NMR and IR spectroscopic measurements of the isolated wall fractions and of the model complex uranyl-phosphatidyl inositol.